104 REPORT—1840. 
variations in the direction of the wind, the paper being carried 
uniformly along beneath the pencil by means of clockwork, so 
that the pencil describes a Curve of Direction of the Wind. The 
force is registered by means of a plate one foot square con- 
nected with the vane-stalk by a jointed parallelogram ; which 
plate is pressed against a spiral spring in such a manner as to 
indicate the force of the wind by the antagonist force of the 
spring in pounds. To indicate this upon the same sheet of 
paper before mentioned, and with regard to time, a thread con- 
nected with the pressure plate is conveyed through the axis of 
the vane-stalk (which is hollow), and then turning over a 
pulley, pulls a pencil up or down as the intensity increases or 
diminishes, leaving an intelligible tracing on the paper, from 
which the mean pressure may be tolerably estimated*. The 
fall of rain is registered by a peculiar contrivance upon the 
same sheet, so as to indicate its amount and distribution over 
the twenty-four hours, The expense of the instrument and its 
liability to derangement are the chief objections to it; it is evi- 
dent that so many objects cannot be gained without consider- 
able complicationt. One of these anemometers has been work- 
ed for a considerable time at Birmingham, and another at Ply- 
mouth{. One has just been established at Edinburgh, and 
others, it is believed, have been sent to Ireland and America. 
200. Mr. R. Adie, of Liverpool, has contrived a statical wind- 
gauge, in which the maximum pressure is pointed out. It is 
on the principle of a gasometer with a moveable top, over 
water, and the pressure of the wind is introduced by a tube 
below. The pressure is indicated by a hand connected with an 
axis, which is turned as the moveable top rises against a gra- 
duated resistance §. 
B. Phenomena of Wind generally. 
201. It is rather remarkable that of late years several persons 
should independently have arrived at partial solutions of the 
great and complicated problem of aerial currents, their distribu- 
tion and causes. A few of the simpler admitted facts have al- 
* As every instrument upon this construction must necessarily act by im- 
pulsive starts, the statical gradation cannot possibly give the actual force of the 
wind, but it is difficult to suggest a better measure. 
+ This instrument is in every respect so much more complicated in its parts 
and delicate in its adjustments than Mr. Whewell’s anemometer, that it is 
difficult to understand how the latter comes to be described in the Royal 
Society’s Instructions (p. 71.) as “ more complex in its construction, and prac- 
tically more liable to derangement.” 
t See Reports of the Ninth Meeting of the British Association. 
§ See a figure in Dr, Traill’s article on Physical Geography, from the Ency- 
clopedia Britannica, 8vo, p. 197. 
